“We have endorsed Marty Walsh,” Lang says. “If he gets into City Hall, one of our own will be mayor, and he will be thinking about helping all of the people of Boston.”

Walsh has compiled a long list of labor endorsements, but this one can be seen as a particular blow to city councilor Felix Arroyo, who has seen his hopes of union backing slip away over the course of the mayoral campaign. UNITE HERE has a heavily minority composition — including many Hispanic workers — and is very similar to the Service Employees International Union, for which Arroyo worked before winning a city council seat.

“There were a number of friends in the race, so what we say about Marty is not a dis on any of the other candidates,” Lang says.

The 20-member committee that voted on the endorsement concluded its in-depth review process — including lengthy interviews with most of the candidates — over a month ago. The lengthy deliberation process, and the final outcome, is sure to be seen by some as the committee members watching Arroyo’s viability in the race, and ultimately deciding he could not win.

“We know that our campaign will be won on the ground by knocking on doors and earning each and every vote,” Arroyo deputy campaign manager Heather Perez said in a statement. “That has been the focus of our campaign from the beginning and we see support increasing every day as our volunteer team continues to grow and Felix’s message continues to resonate with voters throughout the city.”